Humidity and temperature may pose joint effects on human health. However, current temperature-related risk assessments generally focus on univariate temperature statistics, leading to inaccurate risk estimation. By combining temperature and humidity intensities as compound temperature-humidity events (hereinafter as compound events), we examined the effects of humidity in temperature-related health risks in the context of climate change in China using ambulance dispatch data, and further determined the high-risk types and thresholds of compound events. After assessing the health risks, compound events are defined as: i) warm and wet event: temperature ≥ 90th, humidity ≥ 55th and 70%; ii) warm and dry event: temperature ≥ 80th, humidity ≤ 10th; iii) cold and wet event: temperature ≤ 15th, humidity ≥ 70th and 70%; iv) cold and dry event: temperature ≤ 5th and humidity ≤ 25th. Results reveal that humidity can amplify the temperature-related health risks. Higher risks were found during cold and dry events and warm and wet events, posing risks as 1.102 (1.045–1.161) and 1.093 (1.068–1.118) respectively. Compound events mainly occurred in Southeast China during 1979–2019, while the frequency and gripped regions are projected to increase by 2100, and climate change will amplify these trends. Since humidity would exacerbate temperature-related health risks, therefore multiple meteorological parameters are needed in defining adverse weather conditions and conducting risk assessment accurately.

Abstract Compared to a single high-temperature anomaly, compound heat anomalies associated with humidity, such as Compound Hot-Dry Events (CHDEs) and Hot-Wet Events (CHWEs), pose a greater threat to human health. However, it is still unclear how human activities and natural forcings affect the likelihood of these health-related compound heat events. Here we utilize ambulance dispatch data along with meteorological data to study the human activities impact on high health-risk CHDEs and CHWEs in China. We show that relying solely on temperature standards without considering humidity may underestimate the health risks of compound heat events on populations. We find that during the past 40 years, anthropogenic activities in China have increased and decreased the occurrence of high health-risk CHDEs and CHWEs to 2.34 and 0.63 times from 1979 to 2014, respectively, particularly in the middle and lower reaches of the Yangtze River region, compared to natural forcing. And in the future, the opposing contribution of anthropogenic activities will be likely to persist under different shared socioeconomic pathways. We also speculate that, in the future up to 2060, under the carbon-neutral scenario, the frequencies of high health-risk CHDEs and CHWEs caused by human activities can be reduced by one-half and over one-fifth, respectively, compared to the high-emissions scenario (SSP-5.85). Our results provide initial guidance to recognize and asses the health risk of compound events under anthropogenic global warming.

Compound heat anomalies associated with humidity, such as compound hot-dry events and hot-wet events, pose greater health risks than single heat anomalies. Here, we utilize ambulance dispatch data along with air temperature and relative humidity to study human impacts on these events in China. We show that relying solely on temperature without considering humidity may underestimate the health risks of these events on populations. Over the past 40 years, anthropogenic activities have increased hot-dry events by 2.34 times and decreased hot-wet events by 0.63 times, especially in the Yangtze River region, compared to natural forcing. We also speculate that, in the future up to 2060, under the carbon-neutral scenario, the frequencies of high health-risk hot-dry events and hot-wet events caused by human activities can be reduced by one-half and over one-fifth, respectively, compared to the high-emissions scenario. These findings provide guidance for assessing health risks under global warming. Over the past 40 years, human activities in China have led to high health-risk compound heat anomalies, especially in the Yangtze River region, which could be reduced by 2060, if carbon-neutral scenarios are implemented, according to analysis of the ambulance dispatch data, air temperature, and relative humidity.

The Paris Agreement has prompted much interest in the societal and health impacts of limiting global warming to 1.5 °C and 2 °C. Previous assessments of differential impacts of two targets indicate that 1.5 °C warming target would substantially reduce the impact on human health compared to 2 °C, but they mainly focused on the magnitude of temperature changes under future climate change scenarios without any consideration of greater frequency of cumulative heat exposures within a day. Here we quantified the health risks of compound daytime and nighttime hot extremes using morbidity data in a megacity of China, and also identified the time-period of heat exposure with higher risks. Then we projected future morbidity burden attributable to compound hot extremes due to the half-degree warming. We estimated that the 2 °C warming scenario by 2100 as opposed to 1.5 °C would increase annual heat-related ambulance dispatches by 31% in Shenzhen city. Substantial additional impacts were associated with occurrence of consecutive hot days and nights, with ambulance dispatches increased by 82%. Our results suggested that compound hot extremes should be considered in assessment of heat-related health impacts, particularly in the context of climate change. Minimizing the warming of climate in a more ambitious target can significantly reduce the health damage.

Diabetes is a major public health problem globally, and heat exposure may be a potential risk factor for death among diabetes. This study examines the association between heat and diabetes mortality in different regions of Thailand and investigates whether heat effects are modified by regional greenness. Daily temperature and daily diabetes deaths data were obtained for 60 provinces of Thailand during 2000-2008. A case-crossover analysis was conducted to quantify the odds of heat-related death among diabetes. Meta-regression was then used to examine potential modification effects of regional greenness (as represented by the Normalized Difference Vegetation Index) on heat-related mortality. A strong association between heat and diabetes mortality was found in Thailand, with important regional variations. Nationally, the pooled odds ratio of diabetes mortality was 1.10 (95% confidence interval (CI): 1.06-1.14) for heat (90th percentile of temperature) and 1.20 (95% CI: 1.10-1.30) for extreme heat (99th percentile of temperature) compared with the minimum mortality temperature, across lag 0-1 days. Central and northeast Thailand were the most vulnerable regions. Regional greenness modified the effects of heat, with lower mortality impacts in areas of higher levels of greenness. In conclusion, heat exposure increases mortality risk in diabetes, with large geographical variations in risk suggesting the need for region-specific public health strategies. Increasing greenness levels may help to reduce the burden of heat on diabetes in Thailand against the backdrop of a warming climate. (C) 2019 Elsevier B.V. All rights reserved.

Background: Stroke is a leading cause of death globally. Extreme temperatures may induce stroke, but evidence on the effects of heat on first-ever strokes is not clear. Low air pressure can lead to depression and an increase in blood pressure, and it may exacerbate the health impact of heat In this study, we aimed to evaluate the effects of heat on first-ever strokes, the possible sensitive populations, and the effect of modification of atmospheric pressure. Methods: We collected data on 142,569 first-ever strokes during 2005-2016 in Shenzhen, a coastal city in southern China, with subtropical oceanic monsoon climate. We fitted a time-series Poisson model in our study, estimating the association between daily mean temperature and first-ever strokes in hot months, with a distributed lag non-linear model with 7 days of lag. We calculated strokes attributable to heat in various gender, age groups, household register types, stroke subtypes, and atmospheric pressure levels. Results: Heat had a significant cumulative association with first-ever strokes, and the risk of strokes increased with the rise in temperature after it was higher than 30 degrees C (the 85th percentile). In total, 1.95% (95% empirical CI 0.63-3.20%) of first-ever strokes were attributable to high temperature. The attributable fraction and attributable number of heat were statistically significant in male, female, middle-aged and old patients, immigrant patients, and CBI patients. The fraction attributable to heat was 333% in the low atmospheric pressure group, and the number of estimated daily attributable strokes at low atmospheric pressure levels was higher than that of medium and high atmospheric pressure levels (p < 0.01). Conclusions: High temperatures in hot months may trigger first-ever strokes, and low atmospheric pressure may exacerbate the effect. We mainly found associations between heat and first-ever strokes for intracerebral hemorrhage, middle-aged and old patients, as well as immigrant patients. (C) 2018 Elsevier B.V. All rights reserved.

Background: Climate change has exacerbated the health effects of high ambient temperatures on occupational health and safety; however, to what extent heat stress can induce workplace injuries and economic costs is poorly studied. This study aimed to quantify the attributable fractions of injury claims and subsequent insurance payouts using data from work-related injury insurance system in Guangzhou, China. Methods: Individual workers' injury claims data were collected for the period of 2011-2012, including demographic characteristics and work-related information. Daily maximum wet bulb globe temperature (WBGT, degrees C) was calculated from meteorological data. To examine the association between WBGT index and work-related injury, we fit a quasi-Poisson regression with distributed lag non-linear model. Then we calculated the numbers of injury claims and costs of insurance compensations attributable to clays with WBGT above the heat stress limit according to the national occupational health standards. Results: There were 9550 work-related injury claims, resulting in an insurance payout of 282.3 million Chinese Yuan. The risks of injury claims increased with rising WBGT. 43% (95% eCI: 2.9%-6.9%) of work-related injuries and 4.1% (95% eCI: 0.2%-7.7%) of work-related injury insurance payouts were attributed to heat exposure for WBGT threshold above the heat stress limit. Male workers, those in small enterprises and with low educational attainment were especially sensitive to the effects of heat exposure. Conclusions: Heat stress can contribute to higher risk of work-related injury and substantial economic costs. Quantified the impacts of injuries and related economic costs should be considered to develop targeted preventive measures in the context of climate change. (C) 2019 Elsevier B.V. All rights reserved.

Maternal exposure to ambient air pollution has been associated with preterm birth (PTB), however, entire pregnancy or trimester-specific associations were generally reported, which may not sufficiently identify windows of susceptibility. Using birth registry data from Guangzhou, a megacity of southern China (population -14.5 million), including 469,975 singleton live births between January 2015 and July 2017, we assessed the association between weekly air pollution exposure and PTB in a retrospective cohort study. Daily average concentrations of PM2.5, PM10, NO2, SO2, and O-3 from 11 monitoring stations were used to estimate district-specific exposures for each participant based on their district residency during pregnancy. Distributed lag models (DLMs) incorporating Cox proportional hazard models were applied to estimate the association between weekly maternal exposure to air pollutant and PTB risk (as a time-to-event outcome), after controlling for temperature, seasonally, and individual-level covariates. We also considered moderate PTB (32-36 gestational weeks) and very PTB (28-31 gestational weeks) as outcomes of interest. Hazard ratios (HRs) and 95% confidential intervals (95% CIs) were calculated for an interquartile range (IQR) increase in air pollutants during the study period. An IQR increase in PM2.5 exposure during the 20th to 28th gestational weeks (27.0 mu g/m(3)) was significantly associated with PTB risk, with the strongest effect in the 25th week (HR = 1.034, 95% CI:1.010-1.059). The significant exposure windows were the 19th-28th weeks for PM10, the 18th-31st weeks for NO2, and the 23rd-31A weeks for O-3, respectively. The strongest associations were observed in the 25th week for PM10 (IQR = 37.0 mu g/m(3); HR = 1.048, 95% CI:1.034-1.062), the 26th week for NO2 (IQR = 29.0 mu g/m(3); HR = 1.060, 95% CI:1.028-1.094), and in the 28th week for O-3 (IQR = 90.0 mu g/m(3); HR = 1.063, 95% CI:1.046-1.081). Similar patterns were observed for moderate PTB (32-36 gestational weeks) and very PTB (28-31 gestational weeks) for PM2.5, PM10, NO2 exposure, but the effects were greater for very PTB. We did not observe any association between pregnancy SO2 exposure and the risk of PTB. Our results suggest that middle to late pregnancy is the most susceptible air pollution exposure window for air pollution and PTB among women in Guangzhou, China.

以全球变暖为主要特征的气候变化正在影响职业人群的工作环境.高温天气是重要的职业有害物理因素,不仅会损害职业人群的健康,还会影响其劳动生产率.本文旨在探讨高温天气对职业人群劳动生产率的影响,提出中国在该领域的未来研究方向.基于对国内外相关文献的系统分析,高温天气可通过急性健康事件、慢性健康损害、应激反应等方式影响劳动生产率.在未来气候变化背景下,高温热浪的发生频率和强度将会增加,有可能进一步降低职业人群的劳动生产率,从而影响我国社会经济发展,需要引起学术界和政策制定者的充分重视.

Mortality in many parts of the world has a seasonal pattern, with a marked excess of deaths during winter. To date, however, there is very little published evidence on the nature of this wintertime excess in low- and middle-income countries. In this study, we aimed to quantify the extent of the death peak in winter and to assess effect modification on excess winter death (EWD) by individual characteristics and cause of deaths in China. We used a Cosinor model to examine seasonal patterns for specific causes of deaths and a case-only analysis of deaths in winter compared with other seasons to assess effect modification by individual characteristics. A total of 398,529 deaths were investigated between January 2010 and December 2013 in Zhejiang Province, China. Deaths peaked in winter, and overall mortality was around 30% higher in winter than in summer. Although diseases of the respiratory and circulatory systems were highly seasonal, surprisingly we observed that deaths from mental and behavioral disorders exhibited greater fluctuation. Males, the elderly and illiterate individuals suffered high EWD. EWDs were also particularly common in emergency rooms, at home, on the way to hospitals, and in nursing homes/family wards. This study highlighted the high EWD in some previously unreported groups, indicating new information to facilitate the targeting of necessary preventive measures to those at greatest risk in order to mitigate wintertime death burdens.

气候变化会对人群健康产生许多不良影响,其中最主要和最直接的影响是高温热浪导致的健康效应.在全球增暖背景下,未来发生高温热浪的频率和强度都将不断增加.因此,应对高温热浪并减少其对健康造成的不良影响已成为重要的公共卫生问题.对高温热浪健康影响的研究现状进行了分析,指出在开展温度健康效应的研究方面,需要选择更为敏感的健康结局指标,通过更有效的研究设计,准确评估极端气温造成的人群健康损失,从而为有针对性地制定气候变化应对策略和公共卫生干预措施提供依据.

The impact of ambient air pollution on pregnant women is a concern in China. However, little is known about the association between air pollution and preeclampsia and the potential modifying effects of meteorological conditions have not been assessed. This study aimed to assess the effects of prenatal exposure to air pollution on preeclampsia, and to explore whether temperature and humidity modify the effects. We performed a retrospective cohort study based on 1.21 million singleton births from the birth registration system in Shenzhen, China, between 2005 and 2012. Daily average measurements of particulate matter <10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), air temperature (T), and dew point (Td) were collected. Logistic regression models were performed to estimate associations between air pollution and preeclampsia during the first and second trimesters, and during the entire pregnancy. In each time window, we observed a positive gradient of increasing preeclampsia risk with increasing quartiles of PM10 and SO2 exposure. When stratified by T and Td in three categories (<5th, 5th -95th, and >95th percentile), we found a significant interaction between PM10 and Td on preeclampsia; the adverse effects of PM10 increased with Td. During the entire pregnancy, there was a null association between PM10 and preeclampsia under Td < 5th percentile. Preeclampsia risk increased by 23% (95% CI: 19-26%) when 5th < Td < 95th percentile, and by 34% (16-55%) when Td > 95th percentile. We also found that air pollution effects on preeclampsia in autumn/winter seasons were stronger than those in the spring/summer. This is the first study to address modifying effects of meteorological factors on the association between air pollution and preeclampsia. Findings indicate that prenatal exposure to PM10 and SO2 increase preeclampsia risk in Shenzhen, China, and the effects could be modified by humidity. Pregnant women should limit air pollution exposure, particularly during humid periods.

With rapid urbanization and development of transport infrastructure, air pollution caused by multiple-pollutant emissions and vehicle exhaust has been aggravated year by year in China. In order to improve air quality, the Chinese authorities have taken a series of actions to control air pollution emission load within a permissible range. However, although China has made positive progress on tackling air pollution, these actions have not kept up with its economy growth and fossil-fuel use. The traditional single-pollutant approach is far from enough in China now, and in the near future, air pollution control strategies should move in the direction of the multiple-pollutant approach. In addition, undesirable air quality is usually linked with the combination of high emissions and adverse weather conditions. However, few studies have been done on the influence of climate change on atmospheric chemistry in the global perspective. Available evidence suggested that climate change is likely to exacerbate certain kinds of air pollutants including ozone and smoke from wildfires. This has become a major public health problem because the interactions of global climate change, urban heat islands, and air pollution have adverse effects on human health. In this chapter, we first review the past and current circumstances of China's responses to air pollution. Then we discuss the control challenges and future options for a better air quality in China. Finally, we begin to unravel links between air pollution and climate change, providing new opportunities for integrated research and actions in China.